All the UFC 81 fighters who underwent drug tests administered by the Nevada State Athletic Commission have passed their tests, according to the NSAC. Executive director Keith Kizer today released the results to MMAjunkie.com (www.mmajunkie.com). UFC 81 took place Feb. 2 at the Mandalay Bay Events Center in Las Vegas. The pay-per-view event featured Antonio Rodrigo Nogueira’s third-round submission of Tim Sylvia to win the UFC’s interim heavyweight title, and Frank Mir spoiled Brock Lesnar’s UFC debut with a first-round submission. All four fighters were tested for drugs of abuse (such as marijuana and cocaine), as well as anabolic steroids and other performance-enhancers. Other UFC 81 fighters who were tested include Ricardo Almeida, Tim Boetsch, Marvin Eastman, Rob Emerson, Tyson Griffin, Jeremy Horn, Chris Lytle and Nate Marquardt. As standard practice, the NSAC randomly choses fighters for the tests, though all main-event and championship-bout participants are usually tested. Fighters who failed previous tests are also more likely to be tested. so looks like Brock's size is legitimately gained, or he's using good masking agents.